There are quite a few. In order of preference, I used/tried:

• XMPP (Android-Conversations; Windows-Gajim)
• Element/Matrix
• Session
• Discord
• Slack
• Twinme
• Teams
• Skype
• Facebook Messenger
• Instagram DMs

I was using landrop before. Works fine but the GUI was just a bit off, not intuitive enough. That’s Localsend’s biggest improvement IMO.

Same for me. Smart audiobook was great on one device, audiobookshelf even better since being into selfhosting.

To answer directly, MAM is a great private tracker for many reasons, including their epub library. Bibliotik is supposed to be good but harder to get in.

For other options, have a look here.

Falling Lightblocks, available on his own website or GitHub.

TheOnion worthy title.

In hindsight, that’s what I’d go for. You could have audiobookshelf, tachiyomi or any of your favorite android reading apps. But the Kindle does what it does well, and for relatively cheap. Maybe in 5 years I’ll reconsider, if my kindle ever dies!